Trough Level and Tacrolimus Variability of Early Converted Once-Daily Tacrolimus: 1-Year Follow-up Study

Long-term transplant outcomes are considered a crucial point for kidney transplantation. Follow-up studies in patients receiving early conversion to once-daily tacrolimus (TAC-OD) are still limited. We aimed to investigate tacrolimus trough level (Cmin), intrapatient variability of tacrolimus dose-normalized Cmin (TAC-Cmin/D), along with other outcomes between twice-daily tacrolimus (TAC-BID) and early converted TAC-OD. This study was a single center, retrospective, cohort study. All new kidney transplant patients who received tacrolimus and presented an estimated glomerular filtration rate of more than 45 mL/min/1.73 m2 on the day of hospital discharge were included. Studied patients were divided into the standard TAC-BID and patients who were converted from TAC-BID to TAC-OD on the day of hospital discharge. We followed patients for 1 year after transplantation. At the first follow-up visit, Cmin of TAC-OD was significantly lower than that of TAC-BID. However, Cmin and estimated glomerular filtration rate were comparable between TAC-BID and TAC-OD throughout 1-year follow-up. TAC-OD also provided a lower intrapatient variability of TAC-Cmin/D compared with TAC-BID when observed after 6 months post transplantation (17.40% and 23.27% for TAC-OD and TAC-BID, respectively; P = .13). The renal function, as well as other adverse outcomes, was similar between 2 formulations. TAC-OD provided a similar Cmin with comparable renal function compared with TAC-BID during 1-year follow-up. In addition, TAC-OD is likely to have a benefit of a lower intrapatient variability of tacrolimus. Early conversion from TAC-BID to TAC-OD with 1:1 ratio can be used with close long-term monitoring. •Intrapatient variability would be a simple method to support long-term outcomes.•Once-daily tacrolimus improved variability when compared with twice-daily dosing.•The renal function between formulations remained stable at 1-year follow-up.•Tacrolimus trough level was similar between 2 formulations among Asian patients.